The present invention refers to a circuit arrangement with a transmitter system which supplies two path- or angle-dependent, sine-shaped signals of equal amplitude and cycle, which signals are offset in electrical phase by approximately 90.degree., whereby a digitizable signal sequence, which is linearly-dependent on the path or angle, is formed from these two signals by means of a rectification.
In particular, digital increment transmitters with roughly sine-shaped output signals which have a 90.degree. electrical phase offset are customary for detecting rotary movements of machine parts. If these transmitter signals are to be evaluated, then the requisite signal processing can be facilitated in that a linear correlation is achieved between the path or angle and a signal sequence is derived from the transmitter signals. A circuit arrangement for this purpose is known from DE-PS 32 18 101. In this circuit arrangement, a roughly triangular signal, whose amplitude has a linear correlation to the position within each one-eighth cycle of the transmitter, is generated from the transmitter signals through rectification and the formation of a minimum value. The subdivision of the transmitter cycle is facilitated by the analog-digital conversion and the linkage with comparator signals which select the appropriate one-eighth cycles. However, in the case of this device, there is a certain sensitivity to errors in the transmitter signals; i.e. to errors in amplitude equality, phase- and offset errors.
In the German patent application P 38 02 549, a circuit arrangement is described which also operates with two path or angle dependent, sine-shaped signals of the same amplitude and cycle, which are offset in electrical phase by 90.degree.; whereby, however, there is a relatively large insensitivity to the aforesaid distortions of the transmitter signals. In this circuit arrangement, however, the resolution is limited to two triangular waveforms, i.e. four linear sectors within a cycle.